This invention is a master control panel which simplifies the operation of loading dock equipment. In addition to having a dock leveler and overhead door, a loading dock may also have a vehicle restraint, loading light, barrier gate and inflatable shelter. If the various devices are power operated rather than manually operated, the wall beside the doorway may be cluttered with various control panels. Not only is the space between doors often very restricted, but the cost of the electrical installation can be significant. This situation can be improved with the installation of a combination control panel which includes all of the controls in a single enclosure. The combination panel not only saves space but may also reduce the cost of electrical installation. One criticism of existing combination panels has been that the operator may be confused by the various number of switches and push buttons, and the proper sequence of operation.
Description of Related Art
FIG. 1 illustrates a loading dock with a driveway 1, dock wall 2, dock floor 3. A pit 4 is recessed in the floor 3. A dock leveler assembly 10 has a deck assembly 11, and a frame assembly 12 which is mounted in the pit 4. Lip keepers 14 are mounted to the front of the frame. The rear of a deck assembly 11 pivots on the frame assembly 12 and has a lip hinge 13 at the front. A lip assembly 15 is supported at one end by the lip hinge 13 and has the other end resting on the lip keepers 14.
The doorway of the loading dock can be closed by a movable door 18, shown partially open. A vehicle restraint assembly 20 is mounted to the wall 2 and has a hook 21, which moves vertically to engage the ICC bar of a truck or tractor trailer (not shown). A light assembly 23 is mounted beside the doorway and has a red light 24 and a green light 25 to signal the truck driver. Two signs 26 and 27 instruct the driver to move only when the green light is illuminated. The sign 26 has reversed lettering to be legible when viewed in the truck mirror. A loading light 28 is mounted beside the doorway to illuminate the interior of the trailer during loading. A barrier gate assembly 30 has a barrier arm 31 which moves from a horizontal position where it prevents access to the doorway to a vertical position where it allows access to the doorway.
An inflatable shelter assembly 35 has two side bags 36 and a head bag 37 which are inflated by a motor and blower (not shown). When a truck or trailer is at the dock, the bags inflate to form a seal between the truck or trailer and the dock wall.
FIG. 2 demonstrates a typical loading dock area with control panels for a hydraulic dock leveler, electric vehicle restraint and power operated door. The dock leveler control panel 40 has three buttons, button 41 raises the dock leveler deck assembly 11, button 42 extends the hinged lip plate 15, and button 43 is an Emergency Stop which stops all of the dock leveler functions. The vehicle restraint control panel 50 has a selector switch 51, an engage button 52 and a release button 53. Three lights 55, 56 and 57 which are red, amber and green respectively, indicate to the dock operator the status of the vehicle restraint. The selector switch 51 has three positions, Off, On, and Lights Only, which allows the operator to bypass the vehicle restraint if the truck or trailer cannot be captured by the vehicle restraint and must be restrained by wheel chocks. The door control panel 60 has three buttons, an Open button 61, a Close button 63 and a Stop button 62.
The normal operating sequence of the equipment is as follows:
When the dock is not in use, the exterior green light 25 is illuminated to indicate that the truck driver may approach or leave the dock. The interior red light 55 is illuminated to indicate that the dock is not in a condition for use. The operator selects the vehicle restraint control panel 50 and presses the engage button 52. The vehicle restraint hook 21, of FIG. 1, rises to engage the truck or trailer. When the hook 21 starts to rise, the exterior red light 24 is illuminated to indicate that the truck driver cannot leave. When the truck or trailer has been effectively restrained, the interior green light 57 is illuminated to indicate that the dock is ready to use. If the vehicle restraint 20 cannot restrain the trailer, the dock operator must manually chock the truck or trailer wheels. The operator may then turn the selector switch 51 from On to Lights Only. Both the interior green light 55 and amber light 56 are now illuminated to indicate that the dock is safe to use, but that the operator should use greater caution because the vehicle restraint 20 has not engaged the truck or trailer.
The operator selects the door control panel 60 and presses the Door Open button 61 to open the door 18.
The operator selects the dock leveler control panel 40 and presses the Raise button 41 to raise the deck assembly 11, extend the lip assembly 15, and releases the button to lower the leveler onto the trailer. Pressing the Lip Extend button 42 allows faster operation by causing the lip 15 to extend before the deck assembly 11 is fully raised. Pressing the Emergency Stop button 43 causes the dock leveler to stop so that it will not descend on top of any misplaced cargo.
If a loading light 28 is installed it may have a manual switch or may be automatically turned on when the door is opened. Similarly, an inflatable shelter 35 may be operated by a manual switch or be automatically turned on when the door is opened.
When the loading operation is finished, the operating sequence is reversed.
The operator presses the dock leveler Raise button 41 to raise the deck assembly 11, fold the lip assembly 15 and then releases the button to lower the dock leveler to the stored position.
The operator presses the Door Close button 63 to close the door 18. Pressing the Stop button 62 causes the door to stop before it closes.
The operator presses the Release button 53 and the vehicle restraint hook 21 lowers to release the trailer. When the hook 21 starts to lower, the interior red light 55 is illuminated to indicate that the dock is not ready for use. When the hook is fully lowered, the exterior green light 25 is illuminated to indicate that the truck driver may leave.
FIG. 3 demonstrates a typical combination control panel with controls for a hydraulic dock leveler, electric vehicle restraint and power operated door. The control buttons and switches have the identical functions of the separate panels in FIG. 2. Often, a Programmable Logic Controller (PLC) is used to allow many different control sequences and interconnect relationships. A PLC accepts input signals from various devices such as limit switches and push buttons and then transmits output signals to various devices such as lights, relays and motors in accordance with the logic defined by the control program. The use of a PLC is well known in the loading dock industry and the specific electrical circuits and program statements are not shown nor discussed herein.
Although the control buttons and switches are arranged in functional groups and are clearly labeled, an untrained operator may find that the number of buttons and their differing locations make the proper sequence of operations seem confusing. Therefore, this invention provides a combination panel with all of the advantages of compact space and economical installation, and with a simplified operating sequence.
Accordingly, it is desirable to provide a simplified combination panel for controlling loading dock equipment and a method for operating loading dock equipment with a simplified control panel.